In recent years, an increasing number of mobile terminal devices have been provided with a touch sensor capable of performing various operations (for example, activation of a music player, etc.) by detecting touch by a pen or a finger. In such a mobile terminal device, various input keys are displayed on a display such as an LCD (Liquid Crystal Display), a transparent touch panel is superimposed on the display, and the various input keys transmitted through this touch panel to be displayed are operated (touched) by a finger or a pen, thereby performing input operations.
Here, since a finger tip is larger than a pen tip in terms of a touch dimensions, in a case in which the interval between adjacent key touch areas is narrow, a plurality of adjacent keys may be touched at the same time, which may potentially cause malfunction. Therefore, in order to solve such a problem, a method has been proposed in which an interval between adjacent key touch areas is controlled to be widened when touching by a finger, thereby avoiding a plurality of keys from being touched at the same time, and preventing malfunction (for example, see Patent Document 1).
Patent Document 1: Japanese Unexamined Patent Application, Publication No. 2005-050265